Valve.



PATENTED 001. a, 1905.

A. I. PERRY.

VALVE.

APPLICATION I'ILED 1120.21. 1904.

Tzg. 1

I IV V E IV TOR n%'*]ur I. Perry ATTORNEYS UNITED STATES PATENT OFFICE.

VALVE.

Specification of Letters Patent.

Patented Oct. 3, 1905.

' Application filed December 21, 1904. Serial No. 237,809.

To all whom, it may concern.-

-the city of New York, borough of Brooklyn, in the county of Kings andState of New York,

have invented a new and Improved Valve, of which the following is afull, clear, and exact description.

My invention relates to valves, and particularly to those applicable tothe controlling of such fluid-pressure brakes as are used uponstreet-cars. Its principal objects are to provide means for applying thepressure proportionately to the movement of the valve-handle.

Reference is to be had to the accompanying drawings, forming a part ofthis specification, in which similar characters of reference indicatecorresponding parts in both views.

Figure 1 is a central vertical section through one embodiment of myinvention, and Fig. 2 is a vertical sectional detail illustratinganother form of the actuating-screw.

1O designates a casing in which are formed chambers 11 and 12, hereshown as of cylindrical section and having open ends, the former beingsituated uppermost and being of greater transverse area. Near the lowerportion of the casing about the chamber 12 is an annular enlargement 13,in which is a passage 14, communicating through ports 15 with thechamber. This passage 14: is connected to a source of fluid-pressure bysome such means as a pipe or conduit 16. About the chamber 11,externally of the casing, is a similar enlargement l'T, containing apassage 18, from which exhaust-ports 19 open to the atmosphere, a pipe20 serving to direct this exhaust to the desired point. Between thesesets of ports is an admission-port 21, having a passage 21" leading fromit and being connected by a pipe or conduit 22 to the brakecylinder orother mechanism to which pressure is to be supplied.

Operating within the casing is a valve-body 23, preferably of pistonform and having a head 24: fitting within the chamber 11 and a lowerhead 25, which lies in the chamber 12. Between the two heads is acontracted portion forming an annular passage 26. If desired, the valvemay be packed to prevent leakage, there being shown in the presentinstance a ring-27, surrounding the lower portion of the head 25, whileabove this is a ring 28, which in the normal position of the valveoverlaps the supply-ports. A similar ring 29 extends about the head 24and overlaps the exhaustports.

Extending vertically of the chamber 11, or along what is really anextension thereof, are ways 30 to receive projections 31 from a flange32, surrounding the upper end of a nut or actuating member 33, which byits engagement with the casing is permitted to recipro catelongitudinally of said casing While being held against rotation therein.Into the lower portion of the nut a stem 34 is shown as threaded, itbeing conveniently secured in place by a lock-nut 35, which may contactwith the bottom of the actuating-nut. The outer end of this stemprojects through the upper extremity of the valve-body, which may restupon an enlargement 36. Between the body and the flange of theactuating-nut is a spiral spring 37. Secured upon the top of the casingby some such means as bolts 37 is ahead 38, having a threaded bore whichmay lie within an outer boss 39 and receive a screw 40, which isprovided within the casing with an opposite thread 40, engaging athreaded recess in the nut 33. The screw at its outer extremity may havea squared portion 4.1 to receive a hand lever or crank 42, which isshown as secured in place by a nut 43 and has a protecting shield orskirt 4.4 depending over the boss. A screw 45 may be threaded throughthe side of the casing with an end projecting into the valve-passage 26to limit the movement of such valve in its chambers.

The lower end of the chamber 12, as illustrated, is closed by a head 46,in which are openings 17 to permit the free passage of air and avoidimpeding the movement of the valvebody.

Considering that my improved valve is to be used in connection withcar-brakes, the pipe 16 is joined to the reservoir charged by theair-pump, while the pipe 22 leads to the brakecylinder. The valve isshown as in its normal position, both the supply and exhaust beingclosed against communication with the brake-cylinder. To entirely openthe valve, the lever is turned slightly to the left or anticlockwise,which rotates the screw, raising it in the head and at the same timecausing the nut to travel up its lower threads. This opens communicationbetween the admission-pipe to the brake-cylinder and the atmosphere andremoves all pressure from the brake system. To apply the brake with anydesired force up IIO to the maximum pressure of the supply, the I leveris moved in the opposite direction or to the right for the properdistance, the relation of the elements being preferably such that thefull range of movement is through one hundred and eighty degrees. Thissimultaneously moves the screw and actuating-nut down, which would tendto compress the spring; but as there is no opposing force except anegligible frictional resistance the piston is forced with it, openingconnection between the supplyports and the admission-port as soon as thering 28 descends below the upper edge of the former ports. The air nowflows to the brake-cylinder; but as the pressure increases its actionupon the valve-heads (the upper of which has the greater effective area)exerts an upward force upon the spring and moves the piston against itstension until equilibrium is established, closing the supply-port andmaintaining the pressure within the brake-cylinder to hold thebrake-shoes against the car-wheels. If the lever is moved still fartherto the right, the compression of the spring is increased and thesupply-ports again opened, augmenting the pressure in the brake-cylinderin the same manner. This may be continueduntil at the extreme of levermovement the maximum force of the supply will have been exerted. Toreduce the brake-pressure, the lever is turned more or less to the left,lifting the screw and actuating-nut and decreasing the compression ofthe sprin The fluid-pressure acting differentially upon the valve-headsforces said valve upwardly, opening the exhaust-ports and allowingescape to the atmosphere, thereby reducing the brake-pressure. As theforce of the air is lessened the spring moves the piston down untilequilibrium is attained. In the same manner additional reductions may bemade. It will be evident that full brake-pressure may be secured by theextreme movement of the lever in one direction while complete, andimmediate release will follow its movement to the opposite limit.

It will be seen that by the use of my im proved valve in connection withan air-brake the driver will have complete control without removing hisattention from the track ahead, he being able to apply the brakesgradually in proportion to the lever movement for service stops or withfull force in case of emergency, and that by shifting the lever slightlyto any position and leaving it there a definite braliing force issecured and maintained until the lever is again moved. Furthermore,because of the relation of the ports to the valve-body its operation isunafi ected by variations in pressure in either the supply-reservoir orthe brake-cylinder as long as the former does not fall below the desiredmaximum.

It will be obvious that instead of employing a diiferential screw formoving the actuatingnut, a simple screw, such as is shown at 28 l inFig. 2 of the drawings, might be used, this having an unthreaded spindle49, which is journaled in the upper casing-head. The effect will be thesame; but the amount of movement of the nut for any particular angularmovement of the lever will be decreased.

Having thus described myinvention, Iclaim as new and desire to secure byLetters Paton t 1. A valve COmDIlSiDQ, a casing having supply, admissionand exhaust ports, and a movable body portion provided with oppositeheads between which is a continuous space which may communicate witheach of the ports, the pressure of the supply being applied only to theinner adjacent faces of the heads to efiiect movement of the body.

2. A valve comprising a casing having supply, admission and exhaustports, and a movable body portion provided with opposite heads betweenwhich is a space which may communicate with each of the ports, saidheads having different effective areas.

3. A valve comprising a casing having supply, admission and exhaustports, a valve-body having a passage which may communicate with theports, a movable actuating member, a stem along which the valve maymove, said stem being secured to the actuating member and provided withan enlargement with which the body may contact, andp. spring interposedbetween the actuating member and body.

4. A valve comprising a casing having supply, admission and exhaustports, a movable body portion provided with opposite heads between whichis a space which may communicate with each of the ports, said headshaving difierent efl ective areas, an actuating member connected withthe movable body, and a spring interposed between the actuating memberand body.

5. A valve comprising a casing having supply, admission and exhaustports, a movable body portion provided with opposite heads between whichis a space which may communicate with each of the ports, said headshaving diiferent effective areas, an actuating member, a stem extendingfrom the actuating member and being provided with an enlargement withwhich the body may contact, and a spring interposed between theactuating member and body.

6. A valve comprising a casing having supply, admission and exhaustports, a valve-body having a passage which may communicate with theports, a nut mounted to reciprocate in the casing, a stem connecting thevalvebody and nut and upon which the former may move, a screw rotatablein the casing and engaging the nut, and means for turning the screw.

7. The combination with a casing having connecting-chambers of differentareas and ports opening into the chambers, of a pistonvalve providedwith a head fitting each chamber and a passage which may communicatewith the ports, and an actuating member convalve, and a springinterposed between the T nected with the valve. actuating member andvalve.

8. The combination with a casing having Intestimony whereoflhavesignedmy name connecting chambers of different areas and to this specificationin the presence of two sub= 5 ports opening into the chambers, of apistonscribing Witnesses.

valve provided With a head fitting each cham- ARTHUR IRVING PERRY. herand a passage which may communicate Witnesses: with the ports, anactuating member sliding R. E. HAWLEY,

in the casing and being connected with the C. L. CARMAN.

